Latest news with #LipingZhang
Yahoo
7 days ago
- Climate
- Yahoo
Researchers issue warning after new study reveals powerful phenomenon causing flooding along coast: 'Poses threats to both lives and infrastructure'
New research indicates that a climate-change weakened network of ocean currents is a cause of a significant portion of flooding along the northeast coast of the United States. A vital ocean system, referenced by some as the Earth's "cardiovascular system," is shifting and contributing to flooding events. CNN reported that a new study, published in mid-May by Science Advances, showed that from 2005 to 2022 the U.S. Northeast experienced up to eight days of flooding annually due to sea level changes driven by a slowdown of the Atlantic Meridional Overturning Circulation. This means roughly 20% to 50% of total flooding events at monitored sites could be linked to the weakening AMOC. While extreme weather like flooding has always occurred, human activities are intensifying it. As a 2024 post from the Union of Concerned Scientists explained, human activity has caused temperatures to rise globally, melting ice sheets and dumping huge amounts of freshwater into the North Atlantic. "Because of this," according to the UCS, "the ocean waters in the north are less salty and less dense than before," upending delicately balanced circulation patterns. Less dense and warmer water takes up greater space, leading sea levels to rise along with the temperatures. This research is part of a growing body of work demonstrating how a weakening AMOC can strengthen flooding events. Higher sea levels can supercharge floods and storm surges, causing powerful waters to reach further inland. They can also make flooding more frequent by setting the baseline much closer to flood status — just as a mostly full glass of water is more likely to spill over with just a little added on top. Study co-author Liping Zhang, who is also a scientist at the National Oceanic and Atmospheric Administration, told CNN that flooding in the Northeast coastal states can "reshape the coastal environment … (and) poses threats to both lives and infrastructure in coastal regions." That could mean sudden basement floods in homes never before prone to such issues or washed-out roads delaying commutes and cutting off vital services to those in need. Public works and recreational areas could also sustain dangerous and costly destruction, threatening human health and safety too. Do you think your city has good air quality? Definitely Somewhat Depends on the time of year Not at all Click your choice to see results and speak your mind. Such hazards could end up forcing some residents and even whole communities to relocate, with marginalized populations facing disproportionate impacts. High sea levels can also displace barrier islands and critically damage wildlife habitats. The NOAA has called for a cost-effective and enhanced observation network across the Atlantic Ocean to spot where AMOC changes originate. Meanwhile, experts at a January 2025 JPI Climate meeting agreed to complete a report covering potential tipping points, consequences, and mitigation strategies. Research like this new study can arm experts with the information they need to understand the coming dangers and plan for how to help communities counter and navigate them. In the U.S., efforts to prevent Northeast flooding are underway, including marsh restoration and flood resilience initiatives. Eco-friendly practices could help limit further disruption of the AMOC by mitigating temperature rise, and one option for homeowners is to reduce the production of heat-trapping pollution by leveraging a clean, renewable source like solar energy. Installing solar panels together with a battery system comes with added benefits, like ensuring a home's access to power in the wake of weather-related grid outages and significantly lowering energy bills. Resources like the free tool from EnergySage can also help residents compare vetted local installers, with the potential to save homeowners up to $10,000. Helping whole communities to learn about the benefits of cleaner options can multiply the effect and galvanize actions close to home with the possibility of far-reaching impacts. Organizing local walking and biking groups, for example, and supporting public transit can help cut back on planet-warming gases. Join our free newsletter for good news and useful tips, and don't miss this cool list of easy ways to help yourself while helping the planet.
NDTV
19-05-2025
- Science
- NDTV
Why The US Coast Faces Flood Threat? Damning Study Sounds The Alarm
The northeast coast of the US is witnessing more flooding events in recent years owing to the slowdown of a major current in the Atlantic Ocean that is boosting the sea level, a new study has shown. The Atlantic Meridional Overturning Circulation (AMOC) influences climate, weather and sea levels around the planet by transporting heat, salt and freshwater through the ocean, but scientists are worried that it is weakening. The study published last week in the American Association for the Advancement of Science used data from tide gauges (an instrument used to monitor sea level change) and complex ocean models to calculate how the AMOC has affected flooding in the region. "The US Northeast Coast (USNEC) has been identified as a hotspot for accelerated sea level rise over the North Atlantic (NA) Ocean in the most recent decades," the study highlighted. The findings showed that between 2005 and 2022, up to 50 per cent of flooding events along the northeastern coast were driven by a weaker AMOC. With the climate is continuously changing and the atmosphere warming, scientists fear that fresh water from melting polar ice sheets could significantly disrupt or collapse the AMOC, leading to devastating consequences. "If the AMOC collapsed, this would dramatically increase the flood frequency along the US coast, even in the absence of strong storms," Liping Zhang at the Geophysical Fluid Dynamics Laboratory of the US National Oceanic and Atmospheric Administration (NOAA) in New Jersey told New Scientist. "Even partial weakening [of the current] can already have substantial impacts." This is not the first instance when scientists have warned about the collapse of AMOC. A study published last year claimed that the impending disaster, accelerated by human-induced climate change, could occur as early as the late 2030s. While the new study paints a picture of gloom, there is a silver lining. Since natural cycles in the AMOC's strength are largely predictable, scientists could forecast which years will see lots of flooding, up to three in advance. This foresight could help authorities make decisions about emergency preparedness and related infrastructure in time.
Yahoo
17-05-2025
- Science
- Yahoo
The decline of key Atlantic currents is underway, and it's been flooding parts of the US for 20 years
When you buy through links on our articles, Future and its syndication partners may earn a commission. The risk of flooding events along the U.S. Northeast coast has doubled since 2005. Now, scientists have discovered that up to 50% of these events occurred because key Atlantic ocean currents are slowing down. In a new study, researchers found that a considerable portion of the increase in flood risk was linked to the deceleration of the Atlantic Meridional Overturning Circulation (AMOC) — a giant network of ocean currents in the Atlantic Ocean that includes the Gulf Stream and brings heat to the Northern Hemisphere. The AMOC relies on surface waters that have traveled north from the Southern Hemisphere sinking in the North Atlantic. Once they reach the seabed, these waters can ride back south on bottom currents. But climate change is blocking the sinking step by releasing meltwater from the Arctic and Greenland Ice Sheet into the North Atlantic. This dilutes the salt concentration and reduces the density of surface waters, keeping them at the top of the water column. "Our results clearly show that AMOC weakening has contributed to above-average sea level rise and more frequent flooding along the U.S. Northeast coast over recent years," study lead author Liping Zhang, a project scientist at the National Oceanic and Atmospheric Administration (NOAA)'s Geophysical Fluid Dynamics Laboratory, told Live Science. The East Coast as a whole is extremely vulnerable to sea level rise and flooding from climate change, but the Northeast coast is a hotspot when it comes to these impacts, Zhang said. That's mainly because weak circulation in the Atlantic Ocean redistributes heat to regions like the Northeast coast, which causes the water there to swell, she said. Related: 'We don't really consider it low probability anymore': Collapse of key Atlantic current could have catastrophic impacts, says oceanographer Stefan Rahmstorf "Global warming actually has two effects [on sea levels]," she said. "One is the melting of ice caps, which is adding water mass from the land to the ocean, and the other is through thermal expansion, which is when water gets warm and starts expanding." Areas of the ocean that receive the most heat, and therefore undergo more thermal expansion, are likely to experience more rapid sea level rise. "From dynamics, we can see that the AMOC has the strongest [sea level rise] effect on the U.S. Northeast coast," Zhang said, "so that's why we focused on this region." The aim of the new study was to explore the impact of a "moderate" AMOC decline on sea levels and flooding frequency along the Northeast coast. A moderate decline is consistent with climate modeling and direct observations over the past 20 years, Zhang said, so the research is a realistic picture of the AMOC's contribution to the recent increase in sea levels and flooding. The researchers first used a global climate model to simulate large-scale atmospheric and ocean dynamics. They then fed this model sea level data for the Northeast coast from 1912 through 2022, "to force the model to be consistent with observations," Zhang said. Next, the scientists increased the resolution of the ocean component in the model, enabling them to focus on coastal regions. The last step was a statistical analysis to tease out the likely contributions of the AMOC from those of global warming more generally, Zhang explained. The results indicated that the AMOC has played a major role in boosting sea levels and flooding risk along the Northeast coast over the past two decades. Twenty years ago, people living on the Northeast coast could expect around five days of flooding per year, but that has recently increased to 10 days per year, Zhang said. Weakening of the AMOC may be responsible for 20% to 50% of this increase — a substantial contribution when compared to the influence of the global warming trend, the researchers wrote in the study. RELATED STORIES —Are Atlantic Ocean currents weakening? A new study finds no, but other experts aren't so sure. —Key Atlantic current is weakening much faster than scientists had predicted —This spot will be key to the inevitable collapse of a key Atlantic current The model predicted that AMOC-driven sea level rise and flooding frequency will continue to increase over the next three years but then stabilize and reach a plateau as the AMOC itself stabilizes, albeit in a weak state. The model's prediction of an increase in flooding is backed by a mountain of research, but the flattening out of sea level rise and flooding risk may not happen in reality, Zhang said. That's because the model used in the study accounted for the effect of thermal expansion on sea levels but did not incorporate ice melt, Zhang said. "In the real world, if we add the risk of melting ice caps, we might see flooding risk continue to go up," she said. Despite the limitations of the study, Zhang thinks the results can help policymakers plan for the future. "I think the two to three-year predictions will provide critical information for long-term decisions — for example, infrastructure planning, land use and financial planning," she said. The results were published Friday (May 16) in the journal Science Advances.
Yahoo
16-05-2025
- Science
- Yahoo
A crucial system of ocean currents is slowing. It's already supercharging sea level rise in the US.
Flooding on the US Northeast coast has risen significantly as a critical network of Atlantic Ocean currents weakens, according to a new study — an alarming glimpse into the future as some scientists warn the current system could be just decades from collapse. The Atlantic Meridional Overturning Circulation, known as the AMOC, works like a vast conveyor belt, transporting heat, salt and freshwater through the ocean and influencing climate, weather and sea levels around the planet. Coastal flooding is caused by a cluster of factors, chief among them climate change-driven sea level rise, but the AMOC also plays a critical role in the Northeast, according to the study published Friday in the American Association for the Advancement of Science. Scientists used data from tide gauges — instruments which monitor sea level change — combined with complex ocean models to calculate how the AMOC has affected flooding in the region over the past decades. They found between 2005 and 2022, up to 50% of flooding events along the northeastern coast were driven by a weaker AMOC. Drilling down, that means AMOC-driven sea level rise contributed to up to eight flood days a year over this period. The models used by the scientists also give a glimpse into the future, allowing them to forecast coastal flooding frequency in the Northeast up to three years in advance, according to the study. The idea that the AMOC is influencing sea level rise in this region is not new, but this study is the first to find it's substantially affecting flood frequency, said Liping Zhang, a study author and project scientist at the Geophysical Fluid Dynamics Laboratory, part of the National Oceanic and Atmospheric Administration. There are two main reasons why the AMOC affects sea level rise, said David Thornally, professor of ocean and climate science at University College London, who was not involved in the research. A strong AMOC is typically associated with dense deep water that flows along the western boundary of the North Atlantic. When the AMOC weakens, water becomes less dense, literally taking up more space and fueling sea level rise. A weaker AMOC also affects the flow of the Gulf Stream, causing water to flow back onto the coastal shelf and increasing sea level rise at the coast. Rising seas are a huge and urgent issue for society as the climate warms, making it vital to better understand how it's being affected, Zhang told CNN. Coastal flooding can 'reshape the coastal environment… (and) poses threats to both lives and infrastructure in coastal regions,' she said. The findings will be very useful for helping society better predict and plan for costly and devastating flooding events, UCL's Thornally told CNN. 'A study like this is a good way to demonstrate the day-to-day impacts of changes AMOC, rather than invoking dramatic scenes from Hollywood disaster movies which are exaggerated and thus easily dismissed,' he told CNN, referring to the movie The Day After Tomorrow, which depicts the world plunging into a deep freeze after the AMOC collapses. As the research relies on climate models, the results will depend on how well these represent the physics of the real world, he cautioned. 'The high resolution means it probably does a good job — and it can mimic observed sea-level patterns — but it won't be perfect,' he said, especially as this is a complex area of the ocean where different currents meet. Gerard McCarthy, an oceanographer at Maynooth University in Ireland, also not involved in the research, said the study is significant because it shows 'how AMOC can help predict sea level extremes along this coast.' A slew of recent research has pointed to signs the AMOC could be on course to significantly weaken over the next decades as climate change warms oceans and melts ice, disrupting its delicate balance of heat and salinity. This would have catastrophic planetary impacts, including on sea level rise. 'The science is still not clear,' McCarthy said, but a collapse would be a 'high-impact event and it is critical that we know what to expect.'
